I get my £10 Christmas bonus from PIP Just checked, it’s a P60U Pay £0.00 Taxable £0.00 Pay and Taxable benefit £0.00 Tax Deducted £0.00 Tax refunded £0.00 Net Tax Refunded £0.00
The fact that you get your Christmas Bonus paid by PIP and there is no taxable benefit listed on your P60U suggests that your ESA was wholly income related.
Some people on ESA can have an underlying entitlement to contributory ESA but not be paid it, but these are people who are in the Work Related Activity Group, where payment of contributory ESA is limited to 12 months. If on a reassessment the person is then placed in the Suport Group, the contributory based ESA then becomes payable once again.
However, as you are in the Support Group - where contributory ESA isn't time limited - if you were getting contributory ESA when you first claimed, you should still be getting it. This should be reflected in both who pays the Christmas Bonus (there is a hierarchy of which benefit pays the Christmas Bonus and contribution based ESA is ahead of PIP) and what is entered on your P60U.
Have you ever been in the Work Related Activity Group at any point since first claiming ESA? The reason for asking is to find out whether contribution based ESA stopped at some point when you went to the WRAG group and failed to restart when you went to / back to the Support Group.